feat(input): mask controller set-up (#27346)

Issue number: N/A

---------

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## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->

N/A

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

Introduces a `MaskController` class to handle the implementation details
of input masking. The implementation is stubbed out to guide future PRs
that will implement the underlying details.

The design is implemented based on
[maskito](https://github.com/Tinkoff/maskito). Ionic Framework supports
newer versions of Firefox than this library targets, so we can diverge
on the implementation and access modern APIs in portions of the
implementation.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

<!-- If this introduces a breaking change, please describe the impact
and migration path for existing applications below. -->


## Other information

<!-- Any other information that is important to this PR such as
screenshots of how the component looks before and after the change. -->

In terms of testing, you could run the mask test template and verify
that different `console.debug` messages are logging when interacting
with the control.

angular/src/directives/proxies.ts

@@ -977,7 +977,7 @@ export declare interface IonInfiniteScrollContent extends Components.IonInfinite
 
 
 @ProxyCmp({
-  inputs: ['accept', 'autocapitalize', 'autocomplete', 'autocorrect', 'autofocus', 'clearInput', 'clearOnEdit', 'color', 'counter', 'counterFormatter', 'debounce', 'disabled', 'enterkeyhint', 'errorText', 'fill', 'helperText', 'inputmode', 'label', 'labelPlacement', 'legacy', 'max', 'maxlength', 'min', 'minlength', 'mode', 'multiple', 'name', 'pattern', 'placeholder', 'readonly', 'required', 'shape', 'size', 'spellcheck', 'step', 'type', 'value'],
+  inputs: ['accept', 'autocapitalize', 'autocomplete', 'autocorrect', 'autofocus', 'clearInput', 'clearOnEdit', 'color', 'counter', 'counterFormatter', 'debounce', 'disabled', 'enterkeyhint', 'errorText', 'fill', 'helperText', 'inputmode', 'label', 'labelPlacement', 'legacy', 'mask', 'maskPlaceholder', 'maskVisibility', 'max', 'maxlength', 'min', 'minlength', 'mode', 'multiple', 'name', 'pattern', 'placeholder', 'readonly', 'required', 'shape', 'size', 'spellcheck', 'step', 'type', 'value'],
   methods: ['setFocus', 'getInputElement']
 })
 @Component({
@@ -985,7 +985,7 @@ export declare interface IonInfiniteScrollContent extends Components.IonInfinite
   changeDetection: ChangeDetectionStrategy.OnPush,
   template: '<ng-content></ng-content>',
   // eslint-disable-next-line @angular-eslint/no-inputs-metadata-property
-  inputs: ['accept', 'autocapitalize', 'autocomplete', 'autocorrect', 'autofocus', 'clearInput', 'clearOnEdit', 'color', 'counter', 'counterFormatter', 'debounce', 'disabled', 'enterkeyhint', 'errorText', 'fill', 'helperText', 'inputmode', 'label', 'labelPlacement', 'legacy', 'max', 'maxlength', 'min', 'minlength', 'mode', 'multiple', 'name', 'pattern', 'placeholder', 'readonly', 'required', 'shape', 'size', 'spellcheck', 'step', 'type', 'value'],
+  inputs: ['accept', 'autocapitalize', 'autocomplete', 'autocorrect', 'autofocus', 'clearInput', 'clearOnEdit', 'color', 'counter', 'counterFormatter', 'debounce', 'disabled', 'enterkeyhint', 'errorText', 'fill', 'helperText', 'inputmode', 'label', 'labelPlacement', 'legacy', 'mask', 'maskPlaceholder', 'maskVisibility', 'max', 'maxlength', 'min', 'minlength', 'mode', 'multiple', 'name', 'pattern', 'placeholder', 'readonly', 'required', 'shape', 'size', 'spellcheck', 'step', 'type', 'value'],
 })
 export class IonInput {
   protected el: HTMLElement;

core/api.txt

@@ -553,6 +553,9 @@ ion-input,prop,inputmode,"decimal" | "email" | "none" | "numeric" | "search" | "
 ion-input,prop,label,string | undefined,undefined,false,false
 ion-input,prop,labelPlacement,"end" | "fixed" | "floating" | "stacked" | "start",'start',false,false
 ion-input,prop,legacy,boolean | undefined,undefined,false,false
+ion-input,prop,mask,(string | RegExp)[] | RegExp | undefined,undefined,false,false
+ion-input,prop,maskPlaceholder,null | string | undefined,'_',false,false
+ion-input,prop,maskVisibility,"always" | "focus" | "never" | undefined,'always',false,false
 ion-input,prop,max,number | string | undefined,undefined,false,false
 ion-input,prop,maxlength,number | undefined,undefined,false,false
 ion-input,prop,min,number | string | undefined,undefined,false,false

core/src/components.d.ts

@@ -17,6 +17,7 @@ import { CheckboxChangeEventDetail } from "./components/checkbox/checkbox-interf
 import { ScrollBaseDetail, ScrollDetail } from "./components/content/content-interface";
 import { DatetimeChangeEventDetail, DatetimeHighlight, DatetimeHighlightCallback, DatetimePresentation, TitleSelectedDatesFormatter } from "./components/datetime/datetime-interface";
 import { SpinnerTypes } from "./components/spinner/spinner-configs";
+import { MaskExpression, MaskPlaceholder, MaskVisibility } from "./utils/input-masking/public-api";
 import { InputChangeEventDetail, InputInputEventDetail } from "./components/input/input-interface";
 import { CounterFormatter } from "./components/item/item-interface";
 import { MenuChangeEventDetail, Side } from "./components/menu/menu-interface";
@@ -53,6 +54,7 @@ export { CheckboxChangeEventDetail } from "./components/checkbox/checkbox-interf
 export { ScrollBaseDetail, ScrollDetail } from "./components/content/content-interface";
 export { DatetimeChangeEventDetail, DatetimeHighlight, DatetimeHighlightCallback, DatetimePresentation, TitleSelectedDatesFormatter } from "./components/datetime/datetime-interface";
 export { SpinnerTypes } from "./components/spinner/spinner-configs";
+export { MaskExpression, MaskPlaceholder, MaskVisibility } from "./utils/input-masking/public-api";
 export { InputChangeEventDetail, InputInputEventDetail } from "./components/input/input-interface";
 export { CounterFormatter } from "./components/item/item-interface";
 export { MenuChangeEventDetail, Side } from "./components/menu/menu-interface";
@@ -1225,6 +1227,18 @@ export namespace Components {
           * Set the `legacy` property to `true` to forcibly use the legacy form control markup. Ionic will only opt components in to the modern form markup when they are using either the `aria-label` attribute or the `label` property. As a result, the `legacy` property should only be used as an escape hatch when you want to avoid this automatic opt-in behavior. Note that this property will be removed in an upcoming major release of Ionic, and all form components will be opted-in to using the modern form markup.
          */
         "legacy"?: boolean;
+        /**
+          * The predefined format of the user's input. For example, you can set a mask that only accepts digits, or you can configure a more complex pattern like a phone number or credit card number.  The mask supports two formats: 1. A valid [regular expression pattern](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions) 2. An array containing regular expression and fixed character patterns  The fixed characters in the mask cannot be erased or replaced by the user. For example in a phone number mask, the `(`, `)` and `-` are examples of fixed characters.
+         */
+        "mask"?: MaskExpression;
+        /**
+          * Character or string to cover unfilled parts of the mask. The default character is `_`. If set to `null`, `undefined` or an empty string, unfilled parts will be empty as in a regular input.
+         */
+        "maskPlaceholder"?: MaskPlaceholder;
+        /**
+          * The visibility of the mask placeholder. With `always`, the placeholder will be visible even when the control does not have focus. With `focus`, the placeholder will only be visible when the control has focus. With `never`, the placeholder will never be visibly displayed.
+         */
+        "maskVisibility"?: MaskVisibility;
         /**
           * The maximum value, which must not be less than its minimum (min attribute) value.
          */
@@ -5255,6 +5269,18 @@ declare namespace LocalJSX {
           * Set the `legacy` property to `true` to forcibly use the legacy form control markup. Ionic will only opt components in to the modern form markup when they are using either the `aria-label` attribute or the `label` property. As a result, the `legacy` property should only be used as an escape hatch when you want to avoid this automatic opt-in behavior. Note that this property will be removed in an upcoming major release of Ionic, and all form components will be opted-in to using the modern form markup.
          */
         "legacy"?: boolean;
+        /**
+          * The predefined format of the user's input. For example, you can set a mask that only accepts digits, or you can configure a more complex pattern like a phone number or credit card number.  The mask supports two formats: 1. A valid [regular expression pattern](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions) 2. An array containing regular expression and fixed character patterns  The fixed characters in the mask cannot be erased or replaced by the user. For example in a phone number mask, the `(`, `)` and `-` are examples of fixed characters.
+         */
+        "mask"?: MaskExpression;
+        /**
+          * Character or string to cover unfilled parts of the mask. The default character is `_`. If set to `null`, `undefined` or an empty string, unfilled parts will be empty as in a regular input.
+         */
+        "maskPlaceholder"?: MaskPlaceholder;
+        /**
+          * The visibility of the mask placeholder. With `always`, the placeholder will be visible even when the control does not have focus. With `focus`, the placeholder will only be visible when the control has focus. With `never`, the placeholder will never be visibly displayed.
+         */
+        "maskVisibility"?: MaskVisibility;
         /**
           * The maximum value, which must not be less than its minimum (min attribute) value.
          */

core/src/components/input/input.tsx

@@ -8,6 +8,8 @@ import type { LegacyFormController } from '../../utils/forms';
 import { createLegacyFormController } from '../../utils/forms';
 import type { Attributes } from '../../utils/helpers';
 import { inheritAriaAttributes, debounceEvent, findItemLabel, inheritAttributes } from '../../utils/helpers';
+import { MaskController } from '../../utils/input-masking';
+import type { MaskExpression, MaskPlaceholder, MaskVisibility } from '../../utils/input-masking/public-api';
 import { printIonWarning } from '../../utils/logging';
 import { createColorClasses, hostContext } from '../../utils/theme';
 
@@ -31,6 +33,7 @@ export class Input implements ComponentInterface {
   private inheritedAttributes: Attributes = {};
   private isComposing = false;
   private legacyFormController!: LegacyFormController;
+  private maskController?: MaskController;
 
   // This flag ensures we log the deprecation warning at most once.
   private hasLoggedDeprecationWarning = false;
@@ -272,6 +275,35 @@ export class Input implements ComponentInterface {
    */
   @Prop({ mutable: true }) value?: string | number | null = '';
 
+  /**
+   * The predefined format of the user's input. For example, you can set a mask
+   * that only accepts digits, or you can configure a more complex pattern like
+   * a phone number or credit card number.
+   *
+   * The mask supports two formats:
+   * 1. A valid [regular expression pattern](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions)
+   * 2. An array containing regular expression and fixed character patterns
+   *
+   * The fixed characters in the mask cannot be erased or replaced by the user. For example
+   * in a phone number mask, the `(`, `)` and `-` are examples of fixed characters.
+   *
+   */
+  @Prop() mask?: MaskExpression;
+
+  /**
+   * The visibility of the mask placeholder. With `always`, the placeholder will be
+   * visible even when the control does not have focus. With `focus`, the placeholder
+   * will only be visible when the control has focus. With `never`, the placeholder will
+   * never be visibly displayed.
+   */
+  @Prop() maskVisibility?: MaskVisibility = 'always';
+
+  /**
+   * Character or string to cover unfilled parts of the mask. The default character is `_`.
+   * If set to `null`, `undefined` or an empty string, unfilled parts will be empty as in a regular input.
+   */
+  @Prop() maskPlaceholder?: MaskPlaceholder = '_';
+
   /**
    * The `ionInput` event fires when the `value` of an `<ion-input>` element
    * has been changed.
@@ -343,9 +375,11 @@ export class Input implements ComponentInterface {
   }
 
   componentWillLoad() {
+    const { el } = this;
+
     this.inheritedAttributes = {
-      ...inheritAriaAttributes(this.el),
+      ...inheritAriaAttributes(el),
-      ...inheritAttributes(this.el, ['tabindex', 'title', 'data-form-type']),
+      ...inheritAttributes(el, ['tabindex', 'title', 'data-form-type']),
     };
   }
 
@@ -366,7 +400,15 @@ export class Input implements ComponentInterface {
   }
 
   componentDidLoad() {
+    const { mask, nativeInput } = this;
+
     this.originalIonInput = this.ionInput;
+
+    if (mask !== undefined && nativeInput) {
+      this.maskController = new MaskController(nativeInput, {
+        mask,
+      });
+    }
   }
 
   disconnectedCallback() {
@@ -377,6 +419,9 @@ export class Input implements ComponentInterface {
         })
       );
     }
+
+    // Todo - need to evaluate if I need to recreate this in connectedCallback after first load
+    this.maskController?.destroy();
   }
 
   /**

core/src/components/input/test/input.spec.ts

@@ -1,4 +1,5 @@
 import { newSpecPage } from '@stencil/core/testing';
+
 import { Input } from '../input';
 
 it('should inherit attributes', async () => {
@@ -7,7 +8,7 @@ it('should inherit attributes', async () => {
     html: '<ion-input title="my title" tabindex="-1" data-form-type="password"></ion-input>',
   });
 
-  const nativeEl = page.body.querySelector('ion-input input');
+  const nativeEl = page.body.querySelector('ion-input input')!;
   expect(nativeEl.getAttribute('title')).toBe('my title');
   expect(nativeEl.getAttribute('tabindex')).toBe('-1');
   expect(nativeEl.getAttribute('data-form-type')).toBe('password');

core/src/components/input/test/input.spec.tsx

@@ -1,4 +1,5 @@
 import { newSpecPage } from '@stencil/core/testing';
+
 import { Input } from '../input';
 
 it('should render bottom content when helper text is defined', async () => {

core/src/components/input/test/mask/index.html

@@ -0,0 +1,81 @@
+<!DOCTYPE html>
+<html lang="en" dir="ltr">
+  <head>
+    <meta charset="UTF-8" />
+    <title>Input - Mask</title>
+    <meta
+      name="viewport"
+      content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no"
+    />
+    <link href="../../../../../css/ionic.bundle.css" rel="stylesheet" />
+    <link href="../../../../../scripts/testing/styles.css" rel="stylesheet" />
+    <script src="../../../../../scripts/testing/scripts.js"></script>
+    <script nomodule src="../../../../../dist/ionic/ionic.js"></script>
+    <script type="module" src="../../../../../dist/ionic/ionic.esm.js"></script>
+    <style>
+      .grid {
+        display: grid;
+        grid-template-columns: repeat(4, minmax(250px, 1fr));
+        grid-row-gap: 20px;
+        grid-column-gap: 20px;
+      }
+      h2 {
+        font-size: 12px;
+        font-weight: normal;
+
+        color: #6f7378;
+
+        margin-top: 10px;
+      }
+      @media screen and (max-width: 800px) {
+        .grid {
+          grid-template-columns: 1fr;
+          padding: 0;
+        }
+      }
+    </style>
+  </head>
+
+  <body>
+    <ion-app>
+      <ion-header>
+        <ion-toolbar>
+          <ion-title>Input - Item</ion-title>
+        </ion-toolbar>
+      </ion-header>
+
+      <ion-content id="content" class="ion-padding" color="light">
+        <div class="grid">
+          <div class="grid-item">
+            <h2>US Phone Number</h2>
+
+            <ion-input id="input-phone-us" label="Phone"></ion-input>
+          </div>
+        </div>
+      </ion-content>
+    </ion-app>
+
+    <script>
+      const inputPhoneUS = document.querySelector('#input-phone-us');
+      inputPhoneUS.mask = [
+        '+',
+        '1',
+        ' ',
+        '(',
+        /\d/,
+        /\d/,
+        /\d/,
+        ')',
+        ' ',
+        /\d/,
+        /\d/,
+        /\d/,
+        '-',
+        /\d/,
+        /\d/,
+        /\d/,
+        /\d/,
+      ];
+    </script>
+  </body>
+</html>

core/src/interface.d.ts

@@ -43,6 +43,7 @@ export {
   AnimationKeyFrames,
   AnimationLifecycle,
 } from './utils/animation/animation-interface';
+export { MaskExpression, MaskPlaceholder, MaskVisibility } from './utils/input-masking/public-api';
 export { HTMLIonOverlayElement, OverlayController, OverlayInterface } from './utils/overlays-interface';
 export { Config, config } from './global/config';
 export { Gesture, GestureConfig, GestureDetail } from './utils/gesture';

core/src/utils/input-masking/classes/index.ts

@@ -0,0 +1 @@
+export { MaskHistory } from './mask-history';

core/src/utils/input-masking/classes/mask-history.ts

@@ -0,0 +1,63 @@
+import type { ElementState, TypedInputEvent } from '../types/mask-interface';
+
+/**
+ * The mask history class. It is used to store the previous and next states of the element.
+ * @internal
+ *
+ * Original design by Tinkoff:
+ * @see https://github.com/Tinkoff/maskito/blob/main/projects/core/src/lib/classes/mask-history.ts
+ */
+export abstract class MaskHistory {
+  private now: ElementState | null = null;
+  private readonly past: ElementState[] = [];
+  private future: ElementState[] = [];
+
+  protected abstract updateElementState(
+    state: ElementState,
+    eventInit: Pick<TypedInputEvent, 'data' | 'inputType'>
+  ): void;
+
+  protected undo(): void {
+    const state = this.past.pop();
+
+    if (state && this.now) {
+      this.future.push(this.now);
+      this.updateElement(state, 'historyUndo');
+    }
+  }
+
+  protected redo(): void {
+    const state = this.future.pop();
+
+    if (state && this.now) {
+      this.past.push(this.now);
+      this.updateElement(state, 'historyRedo');
+    }
+  }
+
+  protected updateHistory(state: ElementState): void {
+    if (!this.now) {
+      this.now = state;
+      return;
+    }
+
+    const isValueChanged = this.now.value !== state.value;
+    const isSelectionChanged = this.now.selection.some((item, index) => item !== state.selection[index]);
+
+    if (!isValueChanged && !isSelectionChanged) {
+      return;
+    }
+
+    if (isValueChanged) {
+      this.past.push(this.now);
+      this.future = [];
+    }
+
+    this.now = state;
+  }
+
+  private updateElement(state: ElementState, inputType: TypedInputEvent['inputType']): void {
+    this.now = state;
+    this.updateElementState(state, { inputType, data: null });
+  }
+}

core/src/utils/input-masking/constants/default-options.ts

@@ -0,0 +1,9 @@
+import type { MaskOptions } from '../types/mask-interface';
+import { identity } from '../utils';
+
+export const MASK_DEFAULT_OPTIONS: Required<MaskOptions> = {
+  mask: /^.*$/,
+  preprocessor: identity,
+  postprocessor: identity,
+  overwriteMode: 'shift',
+};

core/src/utils/input-masking/constants/index.ts

@@ -0,0 +1 @@
+export * from './default-options';

core/src/utils/input-masking/dom/event-listener.ts

@@ -0,0 +1,30 @@
+import type { TypedInputEvent } from '../types/mask-interface';
+
+/**
+ * Event listener utility class that simplifies teardown of
+ * manually added event listeners.
+ * @internal
+ *
+ * Original design by Tinkoff:
+ * @see https://github.com/Tinkoff/maskito/blob/main/projects/core/src/lib/utils/dom/event-listener.ts
+ */
+export class EventListener {
+  private readonly listeners: (() => void)[] = [];
+
+  constructor(private readonly element: HTMLElement) {}
+
+  listen<E extends keyof HTMLElementEventMap>(
+    eventType: E,
+    fn: (event: E extends 'beforeinput' ? TypedInputEvent : HTMLElementEventMap[E]) => unknown,
+    options?: AddEventListenerOptions
+  ): void {
+    const untypedFn = fn as (event: HTMLElementEventMap[E]) => unknown;
+
+    this.element.addEventListener<E>(eventType, untypedFn, options);
+    this.listeners.push(() => this.element.removeEventListener(eventType, untypedFn));
+  }
+
+  destroy(): void {
+    this.listeners.forEach((removeListener) => removeListener());
+  }
+}

core/src/utils/input-masking/dom/index.ts

@@ -0,0 +1,3 @@
+export * from './event-listener';
+export * from './is-event-producing-character';
+export * from './is-before-input-event-supported';

core/src/utils/input-masking/dom/is-before-input-event-supported.ts

@@ -0,0 +1,14 @@
+/**
+ * "beforeinput" is the appropriate event for preprocessing of the input masking (rather than `keydown`):
+ * - `keydown` is not triggered by predictive text from native mobile keyboards.
+ * - `keydown` is triggered by system key combinations (we don't need them, and they should be manually filtered).
+ * - Dropping text inside input triggers `beforeinput` (but not `keydown`).
+ * ___
+ * "beforeinput" is not supported by Chrome 49+ (only from 60+) and by Firefox 52+ (only from 87+).
+ *
+ * @see https://caniuse.com/?search=beforeinput
+ * @see https://ionicframework.com/docs/reference/browser-support
+ */
+export function isBeforeInputEventSupported(element: HTMLInputElement | HTMLTextAreaElement): boolean {
+  return 'onbeforeinput' in element;
+}

core/src/utils/input-masking/dom/is-event-producing-character.ts

@@ -0,0 +1,9 @@
+/**
+ * Checks if the event is a character that should be inserted into the input.
+ */
+export function isEventProducingCharacter({ key, ctrlKey, metaKey, altKey }: KeyboardEvent): boolean {
+  const isSystemKeyCombinations = ctrlKey || metaKey || altKey;
+  const isSingleUnicodeChar = /^.$/u.test(key); // 4-byte characters case (e.g. smile)
+
+  return !isSystemKeyCombinations && key !== 'Backspace' && isSingleUnicodeChar;
+}

core/src/utils/input-masking/index.ts

@@ -0,0 +1 @@
+export { MaskController } from './mask-controller';

core/src/utils/input-masking/mask-controller.ts

@@ -0,0 +1,158 @@
+import { MaskHistory } from './classes';
+import { MASK_DEFAULT_OPTIONS } from './constants';
+import { isBeforeInputEventSupported, isEventProducingCharacter, EventListener } from './dom';
+import type { ElementState, MaskOptions, SelectionRange, TypedInputEvent } from './types/mask-interface';
+import { getNotEmptySelection } from './utils';
+
+/**
+ * The mask controller class. It is used to control the mask of the element.
+ *
+ * @internal
+ *
+ * Original design by Tinkoff:
+ * @see https://github.com/Tinkoff/maskito/blob/main/projects/core/src/lib/mask.ts
+ */
+export class MaskController extends MaskHistory {
+  private readonly eventListener = new EventListener(this.element);
+
+  private readonly options: Required<MaskOptions> = {
+    ...MASK_DEFAULT_OPTIONS,
+    ...this.maskOptions,
+  };
+
+  constructor(private readonly element: HTMLInputElement, private readonly maskOptions: MaskOptions) {
+    super();
+    console.debug('MaskController', {
+      element,
+      maskOptions,
+      options: this.options,
+    });
+    this.ensureValueFitsMask();
+    this.updateHistory(this.elementState);
+
+    this.eventListener.listen('keydown', (event) => {
+      console.debug('keydown', event);
+    });
+
+    if (isBeforeInputEventSupported(element)) {
+      this.eventListener.listen('beforeinput', (event) => {
+        console.debug('beforeinput', event);
+      });
+    } else {
+      /**
+       * TODO: Remove once Firefox 87+ is the minimum supported version
+       * Also, replace union types `Event | TypedInputEvent` with `TypedInputEvent` inside:
+       *** {@link handleDelete}
+       *** {@link handleInsert}
+       */
+      this.eventListener.listen('keydown', (event) => this.handleKeyDown(event));
+      this.eventListener.listen('paste', (event) =>
+        this.handleInsert(event, event.clipboardData?.getData('text/plain') || '')
+      );
+    }
+
+    this.eventListener.listen('input', () => {
+      console.debug('input');
+    });
+  }
+
+  private get elementState(): ElementState {
+    const { value, selectionStart, selectionEnd } = this.element;
+    return {
+      value,
+      selection: [selectionStart ?? 0, selectionEnd ?? 0],
+    };
+  }
+
+  destroy(): void {
+    // Remove all event listeners
+    this.eventListener.destroy();
+  }
+
+  protected updateElementState(
+    { value, selection }: ElementState,
+    eventInit: Pick<TypedInputEvent, 'data' | 'inputType'> = {
+      inputType: 'insertText',
+      data: null,
+    }
+  ): void {
+    const initialValue = this.elementState.value;
+
+    this.updateValue(value);
+    this.updateSelectionRange(selection);
+
+    if (initialValue !== value) {
+      this.dispatchInputEvent(eventInit);
+    }
+  }
+
+  private handleKeyDown(event: KeyboardEvent): void {
+    const pressedKey = event.key;
+    const isForward = pressedKey === 'Delete';
+
+    switch (pressedKey) {
+      case 'Backspace':
+      case 'Delete':
+        return this.handleDelete({
+          event,
+          isForward,
+          selection: getNotEmptySelection(this.elementState, isForward),
+        });
+    }
+
+    if (!isEventProducingCharacter(event)) {
+      return;
+    }
+
+    this.handleInsert(event, pressedKey);
+  }
+
+  private ensureValueFitsMask(): void {
+    // TODO implementation
+  }
+
+  private handleDelete({
+    event,
+    selection,
+    isForward,
+    force = false,
+  }: {
+    event: Event | TypedInputEvent;
+    selection: SelectionRange;
+    isForward: boolean;
+    force?: boolean;
+  }): void {
+    // TODO implementation
+    console.debug('handleDelete', {
+      event,
+      selection,
+      isForward,
+      force,
+    });
+  }
+
+  private handleInsert(event: Event | TypedInputEvent, data: string): void {
+    // TODO implementation
+    console.debug('handleInsert', event, data);
+  }
+
+  private updateSelectionRange([from, to]: SelectionRange): void {
+    // TODO implementation
+    console.debug('updateSelectionRange', [from, to]);
+  }
+
+  private updateValue(newValue: string): void {
+    // TODO implementation
+    console.debug('updateValue', newValue);
+  }
+
+  private dispatchInputEvent(
+    eventInit: Pick<TypedInputEvent, 'data' | 'inputType'> = {
+      inputType: 'insertText',
+      data: null,
+    }
+  ): void {
+    // TODO implementation
+    console.debug('dispatchInputEvent', eventInit);
+  }
+}

core/src/utils/input-masking/public-api.ts

@@ -0,0 +1 @@
+export { MaskVisibility, MaskExpression, MaskPlaceholder } from './types/mask-interface';

core/src/utils/input-masking/types/mask-interface.ts

@@ -0,0 +1,53 @@
+export interface TypedInputEvent extends InputEvent {
+  inputType:
+    | 'deleteByCut' // Ctrl (Command) + X
+    | 'deleteContentBackward' // Backspace
+    | 'deleteContentForward' // Delete (Fn + Backspace)
+    | 'deleteHardLineBackward' // Ctrl (Command) + Backspace
+    | 'deleteHardLineForward'
+    | 'deleteSoftLineBackward' // Ctrl (Command) + Backspace
+    | 'deleteSoftLineForward'
+    | 'deleteWordBackward' // Alt (Option) + Backspace
+    | 'deleteWordForward' // Alt (Option) + Delete (Fn + Backspace)
+    | 'historyRedo' // Ctrl (Command) + Shift + Z
+    | 'historyUndo' // Ctrl (Command) + Z
+    | 'insertCompositionText'
+    | 'insertFromDrop'
+    | 'insertFromPaste' // Ctrl (Command) + V
+    | 'insertLineBreak'
+    | 'insertReplacementText'
+    | 'insertText';
+}
+
+export type SelectionRange = [from: number, to: number];
+
+export interface ElementState {
+  readonly value: string;
+  readonly selection: SelectionRange;
+}
+
+export type MaskExpression = (RegExp | string)[] | RegExp;
+
+export type MaskPreprocessor = (
+  _: {
+    elementState: ElementState;
+    data: string;
+  },
+  actionType: 'deleteBackward' | 'deleteForward' | 'insert' | 'validation'
+) => {
+  elementState: ElementState;
+  data?: string;
+};
+
+export type MaskPostprocessor = (elementState: ElementState, initialElementState: ElementState) => ElementState;
+
+export interface MaskOptions {
+  readonly mask: MaskExpression | ((elementState: ElementState) => MaskExpression);
+  readonly preprocessor?: MaskPreprocessor;
+  readonly postprocessor?: MaskPostprocessor;
+  readonly overwriteMode?: 'replace' | 'shift' | ((elementState: ElementState) => 'replace' | 'shift');
+}
+
+export type MaskVisibility = 'always' | 'focus' | 'never';
+
+export type MaskPlaceholder = string | null | undefined;

core/src/utils/input-masking/utils/get-not-empty-selection.spec.ts

@@ -0,0 +1,64 @@
+import type { ElementState } from '../types/mask-interface';
+
+import { getNotEmptySelection } from './get-not-empty-selection';
+
+describe('getNotEmptySelection', () => {
+  it('should return the same selection when selection positions are not equal', () => {
+    const elementStateStub: ElementState = {
+      value: 'testValue',
+      selection: [1, 3],
+    };
+
+    expect(getNotEmptySelection(elementStateStub, true)).toEqual(elementStateStub.selection);
+    expect(getNotEmptySelection(elementStateStub, false)).toEqual(elementStateStub.selection);
+  });
+
+  describe('backward direction', () => {
+    it('should not change when start value is 0', () => {
+      const elementStateStub: ElementState = {
+        value: 'testValue',
+        selection: [0, 4],
+      };
+
+      expect(getNotEmptySelection(elementStateStub, false)).toEqual([0, 4]);
+    });
+
+    it('should decrease by one start value', () => {
+      const elementStateStub: ElementState = {
+        value: 'testValue',
+        selection: [1, 1],
+      };
+
+      expect(getNotEmptySelection(elementStateStub, false)).toEqual([0, 1]);
+    });
+  });
+
+  describe('forward direction', () => {
+    it('should increase by one end position, when value`s length is more than the end position', () => {
+      const elementStateStub: ElementState = {
+        value: 'testValue',
+        selection: [2, 2],
+      };
+
+      expect(getNotEmptySelection(elementStateStub, true)).toEqual([2, 3]);
+    });
+
+    it('should return value length as end position, when value`s length is less or equal to the end position ', () => {
+      const elementStateStub: ElementState = {
+        value: 'sx',
+        selection: [4, 4],
+      };
+
+      expect(getNotEmptySelection(elementStateStub, true)).toEqual([2, 2]);
+    });
+
+    it('should increase by one end position, when value`s length equal end position is increased by one', () => {
+      const elementStateStub: ElementState = {
+        value: 'test1',
+        selection: [4, 4],
+      };
+
+      expect(getNotEmptySelection(elementStateStub, true)).toEqual([4, 5]);
+    });
+  });
+});

core/src/utils/input-masking/utils/get-not-empty-selection.ts

@@ -0,0 +1,19 @@
+import type { ElementState, SelectionRange } from '../types/mask-interface';
+
+/**
+ * Returns a selection that is not empty from the given element state.
+ * @param elementState The element state to get the selection from.
+ * @param isForward Whether the selection is forward or not.
+ * @returns The non-empty selection.
+ */
+export function getNotEmptySelection({ value, selection }: ElementState, isForward: boolean): SelectionRange {
+  const [from, to] = selection;
+
+  if (from !== to) {
+    return [from, to];
+  }
+
+  const notEmptySelection = isForward ? [from, to + 1] : [from - 1, to];
+
+  return notEmptySelection.map((index) => Math.min(Math.max(index, 0), value.length)) as [number, number];
+}

core/src/utils/input-masking/utils/identity.ts

@@ -0,0 +1,3 @@
+export function identity<T>(x: T): T {
+  return x;
+}

core/src/utils/input-masking/utils/index.ts

@@ -0,0 +1,2 @@
+export * from './get-not-empty-selection';
+export * from './identity';

packages/vue/src/proxies.ts

@@ -428,6 +428,9 @@ export const IonInput = /*@__PURE__*/ defineContainer<JSX.IonInput, JSX.IonInput
   'size',
   'type',
   'value',
+  'mask',
+  'maskVisibility',
+  'maskPlaceholder',
   'ionInput',
   'ionChange',
   'ionBlur',